One of the many benefits of helping to manage a project of such large scale is that I get to see the various processes of construction from beginning to end – I believe I said almost the exact same thing in my blog about the Gabion Wall. One good example of this has been sourcing the materials for our rammed earth walls. The basic concept of RE is that you simply mix clay with an aggregate sand (aggregate meaning the sand contains lots of different sizes of stone, from dust to gravel) and add water. In Dhulikhel, however, Nripal uses stone dust and mixes it with small stone chips up to a half inch in size. Both of these come from the same source – rock crushing factories, where large stones are fed into a maze of conveyer belts and pulverizing machines and sifters. The stones are typically taken from local rivers, which sounds damaging until you realize its either river beds or carving out mountains.
I wanted to mirror Nripal’s process because, not only is it familiar, but the color he’s achieved is stunning. Part of this is because stone dust is usually a faint yellow tint like a tropical beach, rather than the morbid gray of sand. Regardless, our situation is a little less than ideal, because the nearest source of stone dust is in Nepalgunj, 86 km away. With the possibility of buying in bulk, I traveled there with Top to inspect. This was, unbelievably, about 5 weeks ago. Check out the videos and pictures:
Most of the fence going around the border of our property is to be built with bricks. Therefore, it was imperative that we visit a brick kiln as well to assess quality, bargain, and supervise the loading of bricks into our delivery truck (otherwise, 10% of bricks are typically broken).
Top insisted on going with “Chinese” bricks, which are smooth-faced, straight bricks, tiers above any other locally available bricks in quality at a 20% increase in price. I’m not sure why they’re called Chinese, but visiting the factory was at once inspiring and also a reminder of why I never wanted to build with bricks in the first place.
We got to see the whole process. Lining the road to the brick factory/kiln were huge fields of muddy swamps, where much of the clay was taken from for our bricks. People may remember cutting clay with a wire in art class – the principle here is the same, with huge clay cut cleanly into bricks with a large machine of shifting wires.
Of course, these slabs need to be cut along each dimension to get consistent, flat bricks, so the process is not so simple as a set of wires moving through a large block of clay.
Once cut to dimension, each bricks is brought outside and stacked to dry in the sun. The rows upon rows of brown bricks, stacked with near perfect uniformity in angle and line, is obviously reminiscent of lines upon lines of soldiers. Chinese soldiers? Perfect analogy.
Next begins the part of the process I’m less fond of, though certainly not unimpressed by- firing bricks in a huge kiln. The type of kiln used is known as a Bull Trench Kiln (BTK), and is a oval trench underground with three internal compartments that are fired alternately. While one compartment is firing, another is cooling off while the third is being unloaded and replaced with new sundried bricks to be fired. The design is beautifully efficient and a group of 10 workers can make 25,000 bricks in a day. In the video below, you can see the workers loading up bricks to be fired, while behind me are the finished bricks. The bricks are stacked loosely to maximize airflow.
The holes in the ceiling are for dumping in our fuel – coal. Massive amounts of it. From the center of the BTK is a huge smokestack, from which plumes of black smoke pour out and float lazily along the flat fields around. The coal is produced locally from conventional techniques (itself an amazing process to watch). Groups of workers (and sometimes their children looking on) spend their days breaking up coal boulders into dust and pebbles with sledgehammers.
The coal is then brought up to the covered area above the brick kiln…
where it can be shoveled into any of the hundreds of holes I mentioned above. Of course, an even distribution of coal/heat is essential, so the process continues to be very methodical.
PLYWOOD AND WIRE SHOP
Continuing with this theme of factory visits, I’ll also share some media from our visit to a plywood/wire factory. Inspired by a comment from my dad during a Skype around Christmas time, I’m experiment with the idea of building our subfloor using torsion boxes made from plywood, and pre-fabricated onsite. A torsion box is nothing complex – two sheets of plywood with vertical boards between them, all attached by gluing. They’re very strong, because the glue acts to join all the pieces, forming something resembling a huge, lightweight I beam (with the sheets of plywood forming our flanges). The channels of our torsion boxes could be filled with anything we want to act as sound insulation – my preference is do a little UPcycling and use washed trash/litter taken from the local area and stuff our boxes with it. Rice husks are another interesting option.
The process of producing plywood is intricate, and essentially involves peeling logs on a rotating lathe, then gluing, heating, and pressing together the peels.
We told the factory we would be ordering upwards of 500 sheets of plywood, and we were thus treated like guests of honor. At first, I told the managers that we’d want up to 100, but Top corrected me afterwards and told me you’ll get much better price estimates if you triple your initial estimate of what you’ll need. Definitely a phenomenon to remember, whichever side of the deal you find yourself on.
Our tour of the plywood factory went on to the company’s wire factory and PVC plant. The wire made is copper and steel. The PVC is used to coat the electrical copper wire. The steel seemed all to be wound into cords for lightweight suspension bridges (maybe even ours).
We also visited a house where bamboo/wicker furniture was being made. There was an old man shaving off small pieces of bent bamboo, and I sat watching him for 20 minutes. The furniture they could produce was beautiful, strong, and lightweight.